Duplex distance modification and blank NB-IoT subcarriers

ABSTRACT

Various communication systems may benefit from an improved signaling protocol. For example, communication systems may benefit from an improved network support for a narrowband internet of things in a hosting long term evolution carrier. A method, in certain embodiments, includes shifting a frequency of a downlink long term evolution channel by a pre-determined amount. The shift causes a duplex distance between the downlink long term evolution channel and an uplink long term evolution channel to change. The method includes blanking at least one overlapping radio resource in at least one of the uplink long term evolution channel or an uplink narrowband internet of things channel. The uplink narrowband internet of things channel and the uplink long term evolution channel at least partially overlap. In addition, the method includes receiving data on the uplink narrowband internet of things channel and an additional uplink narrowband internet of things channel at a network entity from a user equipment.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to PCT International ApplicationNo. PCT/US2016/039580, filed on Jun. 27, 2016. The entire content of thepriority application is hereby incorporated by reference.

BACKGROUND Field

Various communication systems may benefit from an improved signalingprotocol. For example, communication systems may benefit from animproved network support for a narrowband internet of things in ahosting long term evolution carrier.

Description of the Related Art

Narrowband internet of things (NB-IoT) can help facilitate low data ratecommunications between machines or objects in 3rd Generation PartnershipProject (3GPP) technology. A downlink transmission on the NB-IoT mayconsist of a 180 kilohertz (kHz) wide orthogonal frequency-divisionmultiplexing (OFDM) signal having 12 subcarriers. The subcarriers may bearranged in a similar way to a single Long Term Evolution (LTE) physicalresource block (PRB), and the physical time structure of the NB-IoT mayalso be similar to a single LTE PRB.

In order to save resources, the NB-IoT may be operated in-band of ahosting LTE carrier or at a guard band of a hosting LTE carrier. A guardband may be an unused part of the radio spectrum between radio bands,for the purpose of preventing interference. In-band signaling, on theother hand, may be the sending of information within the same band.Because of the similar structures of the NB-IoT and the hosting LTEcarrier, including similar subcarrier spacing and symbol length, thecombined system may benefit from orthogonality Orthogonality can be usedto reduce interference between NB-IoT and LTE without filtering.

Compared to operating the NB-IoT at the guard band of a hosting LTE,operating the NB-IoT in-band will cause the NB-IoT to occupy theresources of a hosting LTE PRB. Occupying the hosting LTE PRB can reducethe maximum LTE throughput. In addition, the LTE PRB that is hosting theNB-IoT may still carry LTE information, such as LTE control andreference signals. In some embodiments, only physical downlink sharedchannel (PDSCH) resources of the PRB may be released to the NB-IoT. TheNB-IoT, therefore, may not be able to exploit the full capabilities ofthe PRB.

Operating the NB-IoT at the guard band of a hosting LTE, however, mayrequire a passband extension with a restriction that both LTE and NB-IoTare to be centered on a given channel raster. For example, the LTE andNB-IoT may be centered on the 100 kHz channel raster, with a tolerabledeviation of 7.5 kHz from the perspective of a user equipment (UE). Inaddition, stop band requirements may be applied to the hosting LTE.

Given some of the limitations of operating the NB-IoT in the guard band,LTE band options, particularly those having low bandwidth, can have toolittle room to host an NB-IoT. For example, LTE 1.4 and LTE 3 only havea 160 kHz and 150 kHz guardband, respectively, at each side of thetransmission bandwidth configuration. Such guard bands do not havesufficient bandwidth to host a 180 kHz NB-IoT channe.

SUMMARY

A method, in certain embodiments, may include shifting a frequency of adownlink long term evolution channel by a pre-determined amount. Theshift may cause a duplex distance between the downlink long termevolution channel and an uplink long term evolution channel to change.The method may also include blanking at least one overlapping radioresource in at least one of the uplink long term evolution channel or anuplink narrowband internet of things channel. The uplink narrowbandinternet of things channel and the uplink long term evolution channelmay at least partially overlap. In addition, the method may includereceiving data on the uplink narrowband internet of things channel andan additional uplink narrowband internet of things channel at a networkentity from a user equipment.

According to certain embodiments, an apparatus may include at least onememory including computer program code, and at least one processor. Theat least one memory and the computer program code may be configured,with the at least one processor, to cause the apparatus at least toshift a frequency of a downlink channel by a pre-determined amount. Theshift may cause a duplex distance between the downlink long termevolution channel and an uplink long term evolution channel to change.The at least one memory and the computer program code may also beconfigured, with the at least one processor, at least to blank at leastone overlapping radio resource in at least one of the uplink long termevolution channel or an uplink narrowband internet of things channel.The uplink narrowband internet of things channel and the uplink longterm evolution channel may at least partially overlap. In addition, theat least one memory and the computer program code may also beconfigured, with the at least one processor, at least to receive data onthe uplink narrowband internet of things channel and an additionaluplink narrowband internet of things channel at a network entity from auser equipment.

An apparatus, in certain embodiments, may include means for shifting afrequency of a downlink long term evolution channel by a pre-determinedamount. The shift may cause a duplex distance between the downlink longterm evolution channel and an uplink long term evolution channel tochange. The apparatus may also include means for blanking at least oneoverlapping radio resource in at least one of the uplink long termevolution channel or an uplink narrowband internet of things channel.The uplink narrowband internet of things channel and the uplink longterm evolution channel may at least partially overlap. In addition, theapparatus may include means for receiving data on the uplink narrowbandinternet of things channel and an additional uplink narrowband internetof things channel at a network entity from a user equipment.

According to certain embodiments, a non-transitory computer-readablemedium encoding instructions that, when executed in hardware, perform aprocess. The process may include shifting a frequency of a downlink longterm evolution channel by a pre-determined amount. The shift may cause aduplex distance between the downlink long term evolution channel and anuplink long term evolution channel to change. The process may alsoinclude blanking at least one overlapping radio resource in at least oneof the uplink long term evolution channel or an uplink narrowbandinternet of things channel. The uplink narrowband internet of thingschannel and the uplink long term evolution channel may at leastpartially overlap. In addition, the process may include receiving dataon the uplink narrowband internet of things channel and an additionaluplink narrowband internet of things channel at a network entity from auser equipment.

According to certain embodiments, a computer program product encodinginstructions for performing a process according to a method includingshifting a frequency of a downlink long term evolution channel by apre-determined amount. The shift may cause a duplex distance between thedownlink long term evolution channel and an uplink long term evolutionchannel to change. The method may also include blanking at least oneoverlapping radio resource in at least one of the uplink long termevolution channel or an uplink narrowband internet of things channel.The uplink narrowband internet of things channel and the long termevolution uplink channel may at least partially overlap. In addition,the method includes receiving data on the uplink narrowband internet ofthings channel and an additional uplink narrowband internet of thingschannel at a network entity from a user equipment.

A method, in certain embodiments, may include receiving an indicationthrough a downlink long term evolution channel of a shift in frequencyin the downlink channel by a pre-determined amount. The shift causes aduplex distance between the long term evolution downlink channel and anuplink long term evolution channel to change. The method can alsoinclude transmitting from a user equipment to a network entity data onan uplink narrowband internet of things channel and an additional uplinknarrowband internet of things channel. The at least one overlappingradio resource in at least one of the uplink long term evolution channelor the uplink narrowband internet of things channel may have beenblanked. The uplink narrowband internet of things channel and the uplinklong term evolution channel may at least partially overlap.

According to certain embodiments, an apparatus may include at least onememory including computer program code, and at least one processor. Theat least one memory and the computer program code may be configured,with the at least one processor, to cause the apparatus at least toreceive an indication through a long term evolution downlink channel ofa shift in frequency in the long term evolution downlink channel by apre-determined amount. The shift may cause a duplex distance between thedownlink long term evolution channel and an uplink long term evolutionchannel to change. The at least one memory and the computer program codemay also be configured, with the at least one processor, to cause theapparatus at least to transmit from a user equipment to a network entitydata on an uplink narrowband internet of things channel and anadditional uplink narrowband internet of things channel. The at leastone overlapping radio resource in at least one of the uplink long termevolution channel or the uplink narrowband internet of things channelmay have been blanked. The uplink narrowband internet of things channeland the uplink long term evolution channel may at least partiallyoverlap.

An apparatus, in certain embodiments, may include means for receiving anindication through a downlink long term evolution channel of a shift infrequency in the downlink long term evolution channel by apre-determined amount. The shift may cause a duplex distance between thedownlink long term evolution channel and an uplink long term evolutionchannel to change. The apparatus may also include means for transmittingfrom a user equipment to a network entity data on an uplink narrowbandinternet of things channel and an additional uplink narrowband internetof things channel. The at least one overlapping radio resource in atleast one of the uplink long term evolution channel or the uplinknarrowband internet of things channel may have been blanked. The uplinknarrowband internet of things channel and the uplink long term evolutionchannel may at least partially overlap.

According to certain embodiments, a non-transitory computer-readablemedium encoding instructions that, when executed in hardware, perform aprocess. The process may include receiving an indication through adownlink long term evolution channel of a shift in frequency in thedownlink channel by a pre-determined amount. The shift may cause aduplex distance between the downlink long term evolution channel and anuplink long term evolution channel to change. The process may alsoinclude transmitting from a user equipment to a network entity data onan uplink narrowband internet of things channel and an additional uplinknarrowband internet of things channel. The at least one overlappingradio resource in at least one of the uplink long term evolution channelor the uplink narrowband internet of things channel may have beenblanked. The uplink narrowband internet of things channel and the uplinklong term evolution channel may at least partially overlap.

According to certain embodiments, a computer program product encodinginstructions for performing a process according to a method includingreceiving an indication through a downlink long term evolution channelof a shift in frequency in the downlink channel by a pre-determinedamount. The shift may cause a duplex distance between the downlink longterm evolution channel and an uplink long term evolution channel tochange. The method may also include transmitting from a user equipmentto a network entity data on an uplink narrowband internet of thingschannel and an additional uplink narrowband internet of things channel.The at least one overlapping radio resource in at least one of theuplink long term evolution channel or the uplink narrowband internet ofthings channel may have been blanked. The uplink narrowband internet ofthings channel and the uplink long term evolution channel may at leastpartially overlap.

BRIEF DESCRIPTION OF THE DRAWINGS

For proper understanding of the invention, reference should be made tothe accompanying drawings, wherein:

FIG. 1 illustrates carriers according to certain embodiments.

FIG. 2 illustrates carriers according to certain embodiments.

FIG. 3 illustrates carriers according to certain embodiments.

FIG. 4 illustrates carriers according to certain embodiments.

FIG. 5 illustrates carriers according to certain embodiments.

FIG. 6 illustrates a flow diagram according to certain embodiments.

FIG. 7 illustrates a flow diagram according to certain embodiments.

FIG. 8 illustrates a system according to certain embodiments.

DETAILED DESCRIPTION

Certain embodiments may allow an NB-IoT to operate in the guard band ofa host LTE by increasing the size of the guard band, or the availablebandwidth in the host LTE. For example, the frequency of the LTEdownlink channel may be shifted by a pre-determined amount. This shiftmay change the duplex distance between the downlink channel and theuplink channel of the LTE. The NB-IoT downlink channel may also beshifted. In some embodiments, radio resources or subcarriers of the LTEuplink channel and/or the NB-IoT uplink channel may be blanked.Additional resources in an additional NB-IoT uplink channel may beprovided to compensate for blanked or unused resources. The aboveembodiments can help to facilitate the operation of the NB-IoT on theguard band of the host LTE.

FIG. 1 illustrates carriers according to certain embodiments.Specifically, FIG. 1 illustrates a part of an LTE carrier 110 (8 of 12subcarriers of the LTE carrier are shown in FIG. 1) and an NB-IoTcarrier 120. NB-IoT carrier 120 can include frequencies ranging from2302.5 kHz to 2482.5 kHz. LTE carrier 110 may be an LTE carrier with a 5MHz channel bandwidth and a carrier frequency at 2 GHz. Other channelbandwidths, such as 1.4 MHz and 3 MHz, may also be used. Duplex distanceor spacing may be the space between the uplink and the downlinkfrequencies of a channel. While FIG. 1 illustrates carrier 110 with a 5MHz channel bandwidth, other embodiments may involve an LTE carrier witha different channel bandwidth.

The outermost LTE with a 5 MHZ channel bandwidth carrier 110 can becentered at 2250 kHz off the LTE center frequency. In some embodimentsboth the LTE and the NB-IoT are centered on the 100 kHz channel raster,and a 7.5 kHz offset may be tolerable. A channel raster may be a givenfrequency used by a communication device. In order to be aligned withthe 100 kHz channel raster, the NB-IoT carrier can be centered at 2392.5kHz off the LTE center frequency.

As can be seen in FIG. 1, NB-IoT carrier 120 has 12 subcarriers. Theouter NB-IoT subcarrier may be 2475 kHz off the LTE center, and willhave a width of 15 kHz. The upper pass band edge of the outer NB-IoTsubcarrier is 2482.5 kHz relative to the LTE center. In certainembodiments, the stop band may be fulfilled at 2.5 MHz, which means that17.5 kHz are left for filter roll-off A stopband can be a band frequencythrough which a filter does not allow signals to pass. This limitedfilter roll-off of 17.5 kHz may lead to a long filter impulse responsehaving many filter taps. The long impulse response may not only eat upthe cyclic prefix, but can also lead to multiple inter-symbolinterferences that decrease the signal-to-interference-plus-noise ratio(SINR).

Certain embodiments can provide an apparatus, method, means, or computerprogram product for lengthening the guard band of the LTE carrier orPRB. Lengthening of the guard band may allow for the operation of theNB-IoT on the guard band of the hosting LTE. The LTE can be referred toas a hosting LTE because it can allow the NB-IoT to use an availablesubcarrier or an available radio resource in the LTE PRB. The availablesubcarrier or the available radio resource may be in the guard band ofthe LTE PRB or in-band of the LTE PRB. Some embodiments may shift thefrequency of the downlink channel of the LTE and/or the downlink channelof the NB-IoT. The shift may be by a pre-determined amount determined bya network entity or a network operator. For example, the shift amountmay be −100 kHz. When the shift amount is −100 kHz, the 17.5 kHZ leftfor the filter roll-off may be increased to 117.5 kHz.

In a downlink channel, the 100 kHz channel raster may be valid for bothNB-IoT and LTE, with minor deviations, such as a few kHz, beingtolerated. Integer multiples of 100 kHz are therefore also possible,with a minor deviation. In certain embodiments, no restrictions mayapply to the shift in an uplink channel, allowing for the LTE and NB-IoTto be placed directly adjacent from each other. Some LTE resources maynot be used in the UL, due to blanking or an empty resource block. Thisallows for an even closer placement, either with overlap or inside LTEband placement, of NB-IoT in UL.

On the other side of the LTE carrier 110, which does not border NB-IoTcarrier 120 (not shown in FIG. 1), the −100 kHz shift decreases therange for roll-off from 242.5 kHz to 142.5 kHz. In certain embodiments,a symmetric filter with a 117.5 kHz filter toll-off may be applied. Ashift in the frequency of the downlink may cause a change in the duplexdistance.

While a shift of the frequency of the LTE downlink and/or NB-IoTdownlink may be helpful, in certain embodiments a similar shift in theuplink may result in several disadvantages. A shift of 100 kHz in theuplink, for example, may cause significant interference to the adjacentfrequency block. In certain other embodiments, no frequency shift may beapplied to certain LTE UEs that occupy a 5 MHz block.

In certain embodiments, some of the downlink and/or uplink subcarriersin the hosting LTE and/or NB-IoT may be blanked. Blanking may includefreeing resources or subcarriers in the downlink and/or uplink channel,or making such resources or subcarriers available for transmission byanother channel Resources may be radio resource, for example, or anyother resource that may be used for transmission of data. In certainembodiments, resources or subcarriers that can be blanked in the hostingLTE may be used by the NB-IoT. In other embodiments, blanking resourcesor subcarriers in the NB-IoT may allow for use of the resources by thehosting LTE. In addition, resources may be blanked in any locationwithin the carrier, including the edge of the hosting LTE channelBlanking resources at the edge of the hosting LTE channel may create alarger frequency range for filter roll-off.

For example, blanking three 15 kHz subcarriers from the LTE and/orNB-IoT channels, along with the three unused subcarriers shown in FIG.1, will allow the NB-IoT channel to be shifted −100 kHz, without theneed to shift the LTE channel. In another example, blanking out three 15kHz NB-IoT subcarriers towards the edge of the hosting LTE channel mayallow for an extra 45 kHz for filter roll-off Due to the risk of uplink(UL) channel band leakage, operating the NB-IoT in the guard band of anLTE channel, for example an LTE with a 5 MHz channel bandwidth, may bedifficult.

In certain embodiments, a UL channel may be set up with a fixed duplexdistance. This fixed duplex distance may apply to all or some of thecarriers in a band. However, in case of an NB-IoT operating in a guardband of LTE, the gap of three unused carriers, as shown in FIG. 1, mayconstitute a wasted spectrum that can lead to interference. In otherembodiments, a network entity may signal a different duplex distance toa user equipment. For example, the network entity may send to the UE LTEsystem information that includes an indication of a different duplexdistance. For example, the network entity may signal the UE tocompensate for a frequency shift of −100 kHz for LTE. Changing theduplex distance can help close the gap between NB-IoT and LTE.

Changing the duplex distance can also allow the LTE and/or the NB-IoT tobe centered in the middle of its original MHz block. The UE can beinformed via the DL about the UL frequency offset of 100 kHz. This shiftin the DL may extend the roll-off region from 25 kHz to 70 kHz. Incertain embodiments, physical uplink control channel (PUCCH) blankingmay be used. Blanking may allow the NB-IoT to shift even further towardsthe center of the LTE. In some embodiments, the PUCCH blanking may berestricted to a pre-determined number of sub-carriers.

In certain other embodiments, the offset in the duplex distance may beutilized to cause at least a partial overlap between frequency regionsof the NB-IoT uplink channel and the LTE UL. This partial overlap mayallow the NB-IoT UL to use resources that have been blanked from the LTEUL. In other embodiments, the partial overlap may allow the LTE UL touse resources that have been blanked from the NB-IoT UL. In certainembodiments, in which the hosting LTE contains an asymmetric loadbetween the LTE DL and LTE UL, there may be unused LTE UL resources. TheLTE UL may have a lower load than the LTE DL, in certain embodiments,for data traffic.

In some embodiments, the NB-IoT UL may operate in-band in the LTE UL.For example, three 15 kHz subcarriers from the LTE UL may be blankedout. The NB-IoT UL can then sit adjacent from LTE UL, which can allowfor the shifting of the NB-IoT channel by −100 kHz. This embodiment canextend the roll-off region from 25 kHz to 125 kHz.

The duplex distance, in certain other embodiments, may remain fixed. Thenetwork entity may then schedule UL resources so that legacy UEstransmit in a spectrum which guarantees that no leak occurs outside thechannel bandwidth. For example, only 4.5 MHz in a 5 MHz channel may bescheduled, meaning that a 250 kHz guard band can be provided on eachside. The remaining spectrum may then be used for future UEs signaling,which signal better radio frequency characteristics than legacy UEs. Inaddition, future UE signaling may be transmitted closer to that channelbandwidth edge, for example in a 5 MHz channel bandwidth having a 150kHz band guard. The above embodiments can allow for increasedutilization of the LTE spectrum, while at the same time allowing for afeasible implementation of NB-IoT.

As discussed above, certain embodiments may include guard band NB-IoToperations. In such embodiments, the NB-IoT channel and the hosting LTEmay be shifted in DL by multiples of 100 kHz. In addition, some of theresources or subcarriers in the LTE UL channel, LTE DL channel, NB-IoTDL channel, and/or the NB-IoT UL channel can be blanked out. Theblanking of resources and/or the subcarriers and the DL shift may beused to create sufficiently large guard band for filter roll-off.

The location of the LTE UL can be signaled to the UE from the networkentity using, for example, LTE system information. In certainembodiments, the signaled location of the LTE UL may help to preventleakage above a limit outside the available bandwidth. The limit may bedetermined by any regulatory body. In certain embodiments, the UEs maysupport default transmitter (Tx) to receiver (Rx) separation. Theplacement of NB-IoT UL may occupy various resource of the LTE UL. Insome embodiments, the placement of the NB-IoT may occur when there areno channel raster restrictions for the LTE and/or the NB-IoT.

In certain embodiments, steeper filtering may be used to increase theefficiency of bandwidth utilization. Steeper filtering can allow formore flexible positioning of the carriers in the available spectrum.However, since UEs may still be equipped with their original widefilters, a shift of the original carrier position may make their filterssee or intercept a part of the adjacent frequency block, which canbelong to a different operator. Although the impact may be reduced atthe block edge because of attenuation from the Tx and Rx filter and fastFourier transform selectivity, performance degradation or throughput maybe visible. In embodiments in which the other operator may not beaffected, the steeper filtering may be tolerated. Therefore, in someembodiments, UL frequency positions can be aligned with legacy filters,while DL may utilize steeper filters. In UL, the legacy UE filter mayleak into the adjacent block, while in DL the network entity does notemit any signal to the other operator's frequency block.

In certain embodiments, the NB-IoT can be placed directly adjacent tothe hosting LTE. In other words, the NB-IoT UL channel may be placeddirectly adjacent to the uplink LTE channel. In such embodiments, atleast one resource or subcarrier of the hosted NB-IoT and/or hosting LTEmay be blanked out. In another embodiment, PUCCH blanking may be appliedto the hosting LTE carrier. This blanking may skip or make availablesome of the outermost LTE UL subcarriers, and allows for an even closerplacement of NB-IoT to the LTE center. In addition, in some otherembodiments, some resources inside the LTE UL may be reserved for NB-IoTUL, while NB-IoT is operated in-band in the UL.

In some embodiments NB-IoT subcarriers which overlap with the LTEcarrier may rarely or never be used. To compensate for such unused orblank subcarriers, two half occupied NB-IoT carriers may be consideredfor UL on either side of the LTE carrier. In other words, the resourcesof the UL NB-IoT may be split on opposite sides of the LTE carrier.

FIG. 2 illustrates carriers according to certain embodiments.Specifically, FIG. 2 illustrates an evolved Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (e-UTRA)having a channel bandwidth of 5 MHz. An LTE carrier 210 (8 of 300subcarriers of the LTE carrier are shown), and an NB-IoT carrier 220 maybe provided. NB-IoT carrier 220 may include frequencies ranging from2310 kHz to 2490 kHz, while the last frequency of the LTE carrier 210may be 2250 kHz. The embodiment shown in FIG. 2 can leave 10 kHz forfilter roll-off Four unused subcarriers are also shown. Each subcarrier,for example, may have a width of 15 kHz, which translates to 60 kHzbeing unused. Also, no offset to the channel raster of NB-IoT carrier220 is shown in FIG. 2.

FIG. 3 illustrates carriers according to certain embodiments. Unlike theembodiment of FIG. 2, LTE carrier 310 and NB-IoT carrier 320 do not haveany unused subcarriers located between the two carriers. An LTE carrier310 (8 of 12 subcarriers of the LTE carrier are shown), and an NB-IoTcarrier 320 may be provided. NB-IoT carrier 320 may include frequenciesranging from 2250 kHz to 2430 kHz, while the last frequency of the LTEcarrier 310 may be 2250 kHz. This embodiment can leave 70 kHz for filterroll-off. The NB-IoT carrier 320 may have an offset of −60 kHz, suchthat the carrier is 40 kHz away of the closest raster point where thechannel raster has a periodicity of 100 kHz. While for DL a mandatorychannel raster can be defined, in certain embodiments the UL channelraster may be optional or not applicable when the UL frequency positionis provided in the DL.

FIG. 4 illustrates carriers according to certain embodiments. Inparticular, FIG. 4 illustrates an embodiment in which the carriers aretightly squeezed to create an overlap region 430 between LTE carrier 410and NB-IoT carrier 420. In the overlap region, at least one subcarrierof either LTE carrier 410 and/or NB-IoT 420 may be left blank or remainunused. Overlap region 430 between LTE carrier 410 and NB-IoT carrier420 in the embodiment of FIG. 4 may include three subcarriers, meaningthat the carriers now have nine subcarriers each that do not overlap.

In the embodiment of FIG. 4, three subcarriers from each of NB-IoTcarrier 420 and LTE carrier 410 overlap with one another. For example,the overlap may occur in a frequency range between 2205 kHz and 2250kHz. NB-IoT carrier may have an offset of −5 kHz to the channel raster,and be centered at 2295 kHz. The passband edge of NB-IoT carrier mayhave an offset of 2385 kHz, leaving 115 kHz for roll-off. In certainembodiments, in order to compensate for unused NB-IoT sub-carriers inthe overlapped region, an additional UL carrier resource may beallocated on the other side of the LTE spectrum (not shown in FIG. 4).In other words, because the NB-IoT subcarriers in the overlap region arerarely or never used, in certain embodiments, an additional NB-IoTsubcarrier resource may be added on the other side of the LTE carrier410 to compensate for the unused NB-IoT subcarrier in the overlapregion. This means that the UL NB-IoT may be split into two differentcarriers on opposite sides of the LTE carrier.

FIG. 5 illustrates carriers according to certain embodiments. Inparticular, FIG. 5 illustrates an embodiment in which the carriers aremore tightly squeezed than the embodiment shown in FIG. 4 to create anoverlap region 530 between LTE carrier 510 and NB-IoT carrier 520. Ascan be seen in FIG. 5, the overlap region 530 between LTE carrier 510and NB-IoT carrier 520 may include six subcarriers, meaning that thecarriers now have six subcarriers each that do not overlap. In certainembodiments, subcarriers in overlap region 530 may be blanked or unused.

NB-IoT carrier may have an offset of −50 kHz to the channel raster, andmay be centered at 2250 kHz. The passband edge of NB-IoT carrier mayhave an offset of 2340 kHz, leaving 160 kHz for roll-off. In certainembodiments, in order to compensate for unused NB-IoT sub-carriers inthe overlapped region, an additional UL carrier resource may beallocated on the other side of the LTE/E-UTRA spectrum (not shown inFIG. 5). The number of additional UL carrier resources may be based onthe size of the overlap region and/or the number of subcarriers in theoverlap region. In other words, in certain embodiment the UL may besplit into two carriers, located on both sides of the LTE spectrum.

FIG. 6 illustrates a flow diagram according to certain embodiments.Specifically, FIG. 6 illustrates a diagram for a process carried out bya network entity. In step 610, the network entity may determine thatshifting the frequency of the DL LTE channel may be needed. The networkentity may then shift the frequency of the LTE DL channel by apredetermined amount. For example, the DL LTE channel may be shifted by−100 kHz. In step 620, the network entity may blank at least oneoverlapping radio resource in at least one of the UL LTE channel or theUL NB-IoT. As shown in FIGS. 4 and 5, the UL NB-IoT channel and the LTEUL channel may at least partially overlap. The at least partial overlapmay include at least one blanked or unused radio resource, and the atleast partial overlap may occur either in a guard band of the LTE ULchannel or in-band of the LTE UL channe.

In certain embodiments, to compensate for the at least one blanked orunused radio resource in the overlap region, an additional uplink narrowband internet of things channel may be used. In other words, anadditional uplink carrier resource may be allocated on the other side ofthe LTE spectrum, meaning that the uplink NB-IoT may be split into twocarriers. The UL NB-IoT channel and the additional UL NB-IoT channel maytherefore be located on opposite sides of the LTE UL channel. The UE maythen transmit data on the UL NB-IoT and the additional UL NB-IoT channelto a network entity. The network entity may then receive the data, instep 630.

FIG. 7 illustrates a flow diagram according to certain embodiments.Specifically, FIG. 7 illustrates a diagram for a process carried out bya UE. In step 710, the UE may receive an indication through a DL LTEchannel of a shift in frequency in the DL LTE channel by apre-determined amount. The shift may cause a duplex distance between thedownlink LTE channel and the uplink LTE channel to change. In step 720,the UE can transmit to a network entity data on a UL NB-IoT and anadditional UL NB-IoT channel. At least one overlapping radio resource orsubcarrier in at least one of the UL LTE channel or the UL NB-IoTchannel may have been blanked. In addition, UL NB-IoT channel and the ULLTE channel may at least partially overlap. As shown in FIGS. 4 and 5,the additional UL NB-IoT channel may be used to compensate for anysubcarriers that are blanked or unused in the overlap region. The UL maytherefore be split into two UL NB-IoT carriers located on opposite sidesof the LTE carrier.

FIG. 8 illustrates a system according to certain embodiments. It shouldbe understood that each signal or block in FIGS. 1-7 may be implementedby various means or their combinations, such as hardware, software,firmware, one or more processors and/or circuitry. In one embodiment, asystem may include several devices, such as, for example, network entity820 or UE 810. The system may include more than one UE 810 and more onenetwork node 820, although only one access node shown for the purposesof illustration. The network entity may also be a network node, accessnode, a base station, a 5GNB, an eNB, server, host, or any of the otheraccess or network node discussed herein.

Each of these devices may include at least one processor or control unitor module, respectively indicated as 811 and 821. At least one memorymay be provided in each device, and indicated as 812 and 822,respectively. The memory may include computer program instructions orcomputer code contained therein. One or more transceiver 813 and 823 maybe provided, and each device may also include an antenna, respectivelyillustrated as 814 and 824. Although only one antenna each is shown,many antennas and multiple antenna elements may be provided to each ofthe devices. Other configurations of these devices, for example, may beprovided. For example, network entity 820 and UE 810 may be additionallyconfigured for wired communication, in addition to wirelesscommunication, and in such a case antennas 814 and 824 may illustrateany form of communication hardware, without being limited to merely anantenna.

Transceivers 813 and 823 may each, independently, be a transmitter, areceiver, or both a transmitter and a receiver, or a unit or device thatmay be configured both for transmission and reception. The transmitterand/or receiver (as far as radio parts are concerned) may also beimplemented as a remote radio head which is not located in the deviceitself, but in a mast, for example. The operations and functionalitiesmay be performed in different entities, such as nodes, hosts or servers,in a flexible manner. In other words, division of labor may vary case bycase. One possible use is to make a network node deliver local content.One or more functionalities may also be implemented as virtualapplication(s) in software that can run on a server.

A user device or user equipment 810 may be a mobile station (MS) such asa mobile phone or smart phone or multimedia device, a computer, such asa tablet, provided with wireless communication capabilities, personaldata or digital assistant (PDA) provided with wireless communicationcapabilities, portable media player, digital camera, pocket videocamera, navigation unit provided with wireless communicationcapabilities or any combinations thereof. In other embodiments, the userequipment may be replaced with a machine communication device that doesnot require any human interaction, such as a sensor or a meter.

In some embodiments, an apparatus, such as a network entity, may includemeans for carrying out embodiments described above in relation to FIGS.1-7. In certain embodiments, at least one memory including computerprogram code can be configured to, with the at least one processor,cause the apparatus at least to perform any of the processes describedherein.

According to certain embodiments, an apparatus 820 may include at leastone memory 822 including computer program code, and at least oneprocessor 821. The at least one memory 822 and the computer program codemay be configured, with the at least one processor 821, to cause theapparatus 820 at least to shift a frequency of a downlink channel by apre-determined amount. The shift may cause a duplex distance between thedownlink channel and an uplink channel to change. The at least onememory 822 and the computer program code may also be configured, withthe at least one processor 821, to also cause the apparatus 820 at leastto blank at least one overlapping radio resource in at least one of theuplink channel or a narrowband internet of things channel. Thenarrowband internet of things channel and the uplink channel at leastpartially overlap. In addition, the at least one memory 822 and thecomputer program code may be configured, with the at least one processor821, to cause the apparatus 820 at least to receive data on thenarrowband internet of things channel and an additional uplinknarrowband internet of things channel at a network entity from a userequipment.

According to certain embodiments, an apparatus 810 may include at leastone memory 812 including computer program code, and at least oneprocessor 811. The at least one memory 812 and the computer program codemay be configured, with the at least one processor 811, to cause theapparatus 810 at least to receive an indication through a downlinkchannel of a shift in frequency in the downlink channel by apre-determined amount. The shift may cause a duplex distance between thedownlink channel and an uplink channel to change. The at least onememory 812 and the computer program code may also be configured, withthe at least one processor 811, to also cause the apparatus 810 at leastto transmit from a user equipment to a network entity data on anarrowband internet of things channel and an additional uplinknarrowband internet of things channel. At least one overlapping radioresource in at least one of the uplink channel or the narrowbandinternet of things channel may have been blanked. In addition, thenarrowband internet of things channel and the uplink channel may atleast partially overlap.

Processors 811 and 821 may be embodied by any computational or dataprocessing device, such as a central processing unit (CPU), digitalsignal processor (DSP), application specific integrated circuit (ASIC),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), digitally enhanced circuits, or comparable device or acombination thereof. The processors may be implemented as a singlecontroller, or a plurality of controllers or processors.

For firmware or software, the implementation may include modules or unitof at least one chip set (for example, procedures, functions, and soon). Memories 812 and 822 may independently be any suitable storagedevice, such as a non-transitory computer-readable medium. A hard diskdrive (HDD), random access memory (RAM), flash memory, or other suitablememory may be used. The memories may be combined on a single integratedcircuit as the processor, or may be separate therefrom. Furthermore, thecomputer program instructions may be stored in the memory and which maybe processed by the processors can be any suitable form of computerprogram code, for example, a compiled or interpreted computer programwritten in any suitable programming language. The memory or data storageentity is typically internal but may also be external or a combinationthereof, such as in the case when additional memory capacity is obtainedfrom a service provider. The memory may be fixed or removable.

The memory and the computer program instructions may be configured, withthe processor for the particular device, to cause a hardware apparatussuch as network entity 820 or UE 810, to perform any of the processesdescribed above (see, for example, FIGS. 1-7). Therefore, in certainembodiments, a non-transitory computer-readable medium may be encodedwith computer instructions or one or more computer program (such asadded or updated software routine, applet or macro) that, when executedin hardware, may perform a process such as one of the processesdescribed herein. Computer programs may be coded by a programminglanguage, which may be a high-level programming language, such asobjective-C, C, C++, C#, Java, etc., or a low-level programminglanguage, such as a machine language, or assembler. Alternatively,certain embodiments may be performed entirely in hardware.

Furthermore, although FIG. 8 illustrates a system including a networkentity 820 and UE 810, certain embodiments may be applicable to otherconfigurations, and configurations involving additional elements, asillustrated and discussed herein. For example, multiple user equipmentdevices and multiple network entities may be present, or other nodesproviding similar functionality, such as nodes that combine thefunctionality of a user equipment and an network entity, such as a relaynode. The UE 810 may likewise be provided with a variety ofconfigurations for communication other than communication network entity820. For example, the UE 810 may be configured for device-to-devicecommunication.

Certain embodiments described above may allow for the shifting of an LTEDL channel by a predetermined frequency amount. The network entity maysignal a different duplex distance to the UE, which can be caused by theshifting of the frequency of the LTE DL channel. In addition, certainembodiments described above may allow for the blanking of resources orsubcarriers in the LTE UL channel and/or the NB-IoT channel. Theblanking and/or the shifting can be used to create a sufficient gap atthe edge of the channel bandwidth for filter roll-off. This can allowthe NB-IoT to successfully operate in the guard band of the LTE ULchanne.

The features, structures, or characteristics of certain embodimentsdescribed throughout this specification may be combined in any suitablemanner in one or more embodiments. For example, the usage of the phrases“certain embodiments,” “some embodiments,” “other embodiments,” or othersimilar language, throughout this specification refers to the fact thata particular feature, structure, or characteristic described inconnection with the embodiment may be included in at least oneembodiment of the present invention. Thus, appearance of the phrases “incertain embodiments,” “in some embodiments,” “in other embodiments,” orother similar language, throughout this specification does notnecessarily refer to the same group of embodiments, and the describedfeatures, structures, or characteristics may be combined in any suitablemanner in one or more embodiments.

One having ordinary skill in the art will readily understand that theinvention as discussed above may be practiced with steps in a differentorder, and/or with hardware elements in configurations which aredifferent than those which are disclosed. Therefore, although theinvention has been described based upon these preferred embodiments, itwould be apparent to those of skill in the art that certainmodifications, variations, and alternative constructions would beapparent, while remaining within the spirit and scope of the invention.While some embodiments may be directed to an LTE environment, otherembodiments can be directed to other 3GPP technology, such as LTEadvanced, 4G, or 5G technology.

Partial Glossary 5G 5th Generation 3GPP 3rd Generation PartnershipProject BTS Base Transceiver Station DL Downlink LTE Long Term EvolutionLTExx Different bandwidth options for LTE, where xx denotes thebandwidth in MHz NB-IoT Narrowband Internet of Things OFDM OrthogonalFrequency Division Multiplex PRB Physical Resource Block PUCCH PhysicalUplink Control Channel SINR Signal to Interferer and Noise Ratio UE UserEquipment UL Uplink

We claim:
 1. An apparatus comprising: at least one memory comprisingcomputer program code; at least one processor; wherein the at least onememory and the computer program code are configured, with the at leastone processor, to cause the apparatus at least to: shift a frequency ofa downlink long term evolution channel by a pre-determined amount,wherein the shift causes a duplex distance between the downlink longterm evolution channel and an uplink long term evolution channel tochange; blank at least one overlapping radio resource in at least one ofthe uplink long term evolution channel or a uplink narrowband internetof things channel, wherein the uplink narrowband internet of thingschannel and the uplink long term evolution channel at least partiallyoverlap; and receive data on the uplink narrowband internet of thingschannel and an additional uplink narrowband internet of things channelat a network entity from a user equipment.
 2. The apparatus according toclaim 1, wherein at least one radio resource in the additional uplinknarrowband internet of things channel compensates for the blanking ofthe at least one radio resource in the uplink narrowband internet ofthings channel.
 3. The apparatus according to claim 1, wherein theadditional uplink narrowband internet of things channel and the uplinknarrowband internet of things channel are located on opposite sides ofthe long term evolution channel.
 4. The apparatus according to claim 1,wherein the at least partial overlap of the uplink narrowband internetof things channel and the uplink long term evolution channel comprisesusing a resource blanked out from the uplink long term evolution channelfor the uplink narrowband internet of things channel, or using aresource blanked out from the uplink narrowband internet of thingschannel for the uplink long term evolution channel.
 5. The apparatusaccording to claim 1, wherein the at least partial overlap of the uplinknarrowband internet of things channel and the uplink long term evolutionchannel occurs on a guard band of the uplink long term evolutionchannel.
 6. The apparatus according to claim 1, wherein the at leastpartial overlap of the uplink narrowband internet of things channel andthe uplink long term evolution channel occurs in-band of the uplink longterm evolution channel.
 7. The apparatus according to claim 1, whereinthe at least one memory and the computer program code are configured,with the at least one processor, to cause the apparatus at least to:place the uplink narrowband internet of things channel directly adjacentto the long term evolution uplink channel.
 8. The apparatus according toclaim 1, wherein the at least one memory and the computer program codeare configured, with the at least one processor, to cause the apparatusat least to: blank the at least one overlapping radio resource in aphysical uplink control channel.
 9. The apparatus according to claim 1,wherein the downlink long term evolution channel and the uplink longterm evolution channel are channels are associated with a hosting longterm evolution network.
 10. The apparatus according to claim 1, whereinthe blanking of the at least one overlapping radio resource in theuplink long term evolution channel or the uplink narrowband internet ofthings channel is restricted to a predetermined number of resources. 11.The apparatus according to claim 1, wherein the frequency of thedownlink long term evolution channel is shifted by an integer multipleof 100 kilohertz.
 12. The apparatus according to claim 1, wherein noleakage above a pre-determined regulatory limit outside the uplink longterm evolution channel occurs.
 13. A method for performing a processaccording to claim
 1. 14. A non-transitory computer-readable mediumencoding instructions that, when executed in hardware, perform a processaccording to claim
 1. 15. A computer program product encodinginstructions for performing a process according to claim
 1. 16. Anapparatus comprising: at least one memory comprising computer programcode; at least one processor; wherein the at least one memory and thecomputer program code are configured, with the at least one processor,to cause the apparatus at least to: receive an indication through adownlink long term evolution channel of a shift in frequency in thedownlink long term evolution channel by a pre- determined amount,wherein the shift causes a duplex distance between the downlink longterm evolution channel and an uplink long term evolution channel tochange; and transmit from a user equipment to a network entity data onan uplink narrowband internet of things channel and an additional uplinknarrowband internet of things channel, wherein at least one overlappingradio resource in at least one of the uplink long term evolution channelor the uplink narrowband internet of things channel has been blanked,and wherein the uplink narrowband internet of things channel and theuplink long term evolution channel at least partially overlap.
 17. Theapparatus according to claim 16, wherein at least one radio resource inthe additional uplink narrowband internet of things channel compensatesfor the blanking of the at least one radio resource in the uplinknarrowband internet of things channel.
 18. The apparatus according toclaim 16, wherein the additional uplink narrowband internet of thingschannel and the uplink narrowband internet of things channel are locatedon opposite sides of the long term evolution channel.
 19. The apparatusaccording to claim 16, wherein the at least partial overlap of theuplink narrowband internet of things channel and the uplink long termevolution channel occurs on a guard band of the uplink long termevolution channel.
 20. The apparatus according to claim 16, wherein theat least partial overlap of the uplink narrowband internet of thingschannel and the uplink long term evolution channel occurs in-band of theuplink long term evolution channel.
 21. A method for performing aprocess according to claim
 16. 22. A non-transitory computer-readablemedium encoding instructions that, when executed in hardware, perform aprocess according to claim
 16. 23. A computer program product encodinginstructions for performing a process according to claim 16.